Abstract:Temperature threshold for nanorod structuring of metal and oxide films grown by glancing angle deposition Electron transport and band structure in phosphorus-doped polycrystalline silicon films J. Appl. Phys. 105, 033715 (2009); 10.1063/1.3068349Density-of-states effective mass and scattering parameter measurements by transport phenomena in thin films Rev. Sci. Instrum. 71, 462 (2000)
“…With the further increasing voltage, the CF between TE and BE will be reconstructed by an accumulation of V o as shown in set-phase 2 and RRAM cell switches to LRS. During reset, two processes take place simultaneously: (1) the O 2− released from TiN electrode rapidly recombine with the positively charged V o because of the enhanced capture section, (2) the O 2− drifting toward BE reacts with Ru and reforms the RuO 2 interface layer due to the local Joule heating [22]. At this condition, the RRAM cell switches to HRS.Fig.…”
In this work, Ru-based RRAM devices with atomic layer deposited AlOy/HfOx functional layer were fabricated and studied. A negative differential resistance (NDR) behavior was observed during the voltage set process, and its physical origin was explored. Based on the physics understanding of the resistive switching, the measured NDR behavior is believed to be associated with the partially unipolar reset effect, which is due to the recombination between oxygen vacancies and the thermally released oxygen ions from the RuO2 interface layer. The measured electrical characteristics and X-ray photoelectron spectroscopy (XPS) results verified the physical interpretation.
“…With the further increasing voltage, the CF between TE and BE will be reconstructed by an accumulation of V o as shown in set-phase 2 and RRAM cell switches to LRS. During reset, two processes take place simultaneously: (1) the O 2− released from TiN electrode rapidly recombine with the positively charged V o because of the enhanced capture section, (2) the O 2− drifting toward BE reacts with Ru and reforms the RuO 2 interface layer due to the local Joule heating [22]. At this condition, the RRAM cell switches to HRS.Fig.…”
In this work, Ru-based RRAM devices with atomic layer deposited AlOy/HfOx functional layer were fabricated and studied. A negative differential resistance (NDR) behavior was observed during the voltage set process, and its physical origin was explored. Based on the physics understanding of the resistive switching, the measured NDR behavior is believed to be associated with the partially unipolar reset effect, which is due to the recombination between oxygen vacancies and the thermally released oxygen ions from the RuO2 interface layer. The measured electrical characteristics and X-ray photoelectron spectroscopy (XPS) results verified the physical interpretation.
“…The angle can take any value in the range [0, 2π]. So C( ) can be replaced in equation (10) and the mean free path becomes:…”
Section: Theorymentioning
confidence: 99%
“…Furthermore, very little is known about the conductivity changes due to a controlled orientation of the columnar structure in thin films [9]. It is even more verified for theoretical models taking into account these special architectures and being able to calculate the transport properties in such anisotropic materials [10].…”
Chromium thin films are prepared by magnetron sputtering using the GLancing Angle Deposition (GLAD) method. The electrical conductivity of the films exhibiting an inclined columnar structure is investigated. An analytical three dimensional model is proposed in order to predict the evolution of the electrical conductivity as a function of the columns orientation. This model is based on two types of electron scattering mechanisms, which are simultaneously operational: the isotropic background scattering at the grain boundary and the scattering due to electron dispersion at the column boundary. The developed analytical expressions enable systematic studies of different process and film parameters, especially the column angle β as well as the sputtering pressure used during the GLAD deposition. The theoretical and experimental results are compared. It is found that the column angle β must reach a threshold value to significantly reduce the electrical conductivity of chromium thin films close to one order of magnitude. The effect of the sputtering pressure on the films
“…The nanorods formed during growth become separated by shadowed regions, which consist of very small polycrystalline grains at the film/substrate interface that initially form but stop growing at the expense of the nanorods due to atomic shadowing. 10,11 Films grown with the GLAD configuration generally have nanoporous columnar morphologies and are typically grown with a deposition angle, ␣, greater than 80°so as to exacerbate atomic shadowing. Nanorod structured films grown using GLAD have been demonstrated for many high melting point metals, including W, Ru, and Ta, [12][13][14] since they have relatively low surface mobilities.…”
Thin films of tin (Sn), aluminum (Al), gold (Au), ruthenium (Ru), tungsten (W), ruthenium dioxide (RuO2), tin dioxide (SnO2), and tungsten trioxide (WO3) were grown by glancing angle deposition (GLAD) to determine the nanostructuring temperature threshold, ΘT, above which adatom surface diffusion becomes large enough such that nanorod morphology is no longer formed during growth. The threshold was found to be lower in metals compared to oxides. Films were grown using both dc and pulsed dc magnetron sputtering with continuous substrate rotation over the temperature range from 291 to 866 K. Film morphologies, structures, and compositions were characterized by high resolution scanning electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy. Films were also grown in a conventional configuration for comparison. For elemental metals, nanorod structuring occurs for films with melting points higher than that of Al (933 K) when grown at room temperature with a rotation rate of ∼5 rpm, corresponding to a value of ΘT≈0.33±0.01. For the oxide films, a value of ΘT≈0.5 was found, above which GLAD nanorod structuring does not occur. The existence of a nanostructuring temperature threshold in both metal and oxide GLAD films can be attributed to greater adatom mobilities as temperature is increased resulting in nonkinetically limited film nucleation and growth processes.
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